How do I set a sample to non-filtering?

[janhohenheim]

I'm loading an HDRi that is crashing in WASM (for some reason not in native tho). It's the one from @griffin#2864 's tutorial: https://github.com/DGriffin91/bevy_glowy_orb_tutorial/blob/main/assets/textures/stone_alley_02_1k.hdr
It seems that it's using 32 bit precision, which does not support filtering. I thought the following should be enough to disable filtering:

#[derive(AsBindGroup, Debug, Clone, TypeUuid)]
#[uuid = "bd5c76fd-6fdd-4de4-9744-4e8beea8daaf"]
pub struct GlowyMaterial {
    #[texture(0, filterable = false)]
    #[sampler(1, sampler_type = "non_filtering")]
    pub env_texture: Option<Handle<Image>>,
}

but apparently not, since at runtime I get:

panicked at 'wgpu error: Validation Error
Caused by:
     In Device::create_bind_group
     sampler binding 1 expects filtering = false, but given a sampler with filtering = true

This leads me to believe that the attributes I set are more descriptive than prescriptive. How can I tell Bevy to actually use a sampler without filtering?

[janhohenheim]

Mirroring the discord discussion here for googleability:

Griffin — Today at 5:20 AM
The AsBindGroup macro you have expands to:

    fn bind_group_layout(render_device: &renderer::RenderDevice) -> BindGroupLayout {
        render_device.create_bind_group_layout(&BindGroupLayoutDescriptor {
            entries: &[
                BindGroupLayoutEntry {
                    binding: 0u32,
                    visibility: ShaderStages::VERTEX | ShaderStages::FRAGMENT,
                    ty: BindingType::Texture {
                        multisampled: false,
                        sample_type: TextureSampleType::Float { filterable: false },
                        view_dimension: TextureViewDimension::D2,
                    },
                    count: None,
                },
                BindGroupLayoutEntry {
                    binding: 1u32,
                    visibility: ShaderStages::VERTEX | ShaderStages::FRAGMENT,
                    ty: BindingType::Sampler(SamplerBindingType::NonFiltering),
                    count: None,
                },
            ],
            label: None,
        })
    }

Which seems to imply we tell wgpu to use NonFiltering.
I'm not really sure why this is happening.
The image won't probably look very good without filtering if you are trying to use it in a similar way as I did in the video.
If it is 32 bit, maybe converting it to 16bit would work with a filtering sampler?

IceSentry — Today at 6:17 AM
I don't know how to fix it, but the issue is that while the macro tells wgpu to use the correct type of sampler it doesn't create one for the image. It just uses the default sampler of the image
One way would be to expand the macro and create/cache the sampler yourself, it's a bit annoying though

Griffin — Today at 6:29 AM
Would changing the sampler descriptor on the Image maybe work then?
IceSentry — Today at 6:34 AM
probably yeah

hohenheim
OP
— Today at 2:14 PM
@griffin I’ll try converting it then and report back. Thanks for the tutorial btw, loved the information density 🙂
Which field of the Image sample descriptor would be relevant here? I couldn’t find it myself

hohenheim
OP
— Today at 7:10 PM
Update: Yeah, using 16 bit works.
But now I'm confused: per https://gpuweb.github.io/gpuweb/#texture-format-caps, 32 bit never supports filtering. So why does this work in native at all? 🤔

Griffin — Today at 8:12 PM
SamplerDescriptor https://docs.rs/bevy/latest/bevy/render/render_resource/struct.SamplerDescriptor.html has filter modes. But I'm not sure how they relate to NonFiltering. Maybe Nearest is related, but I'm not sure.

hohenheim
OP
— Today at 8:13 PM
Yeah, I stood before the same problem. It looks related, but it's not transparent.

Griffin — Today at 8:14 PM
Nice! Not sure, maybe some gpus support it and wgpu doesn't limit desktop to the webgpu spec.

hohenheim
OP
— Today at 8:15 PM
Ah, TIL. I thought it was all WebGPU compliant, but it seems I'm wrong.

Griffin — Today at 8:17 PM
@cwfitzgerald it looks like webgpu says 32bit float textures are not filterable (rgba32float "unfilterable-float"), but it seems linear filtering does work on desktop. Is this what unfilterable-float is referring to, or is wgpu just letting you when the gpu supports it?

cwfitzgerald — Today at 8:21 PM
If you enable the texture adapter specific format features feature, wgpu will let you do what your card supports